Depends on the calculator.

Most calculators in use for HS Math classes or above will likely be programmable calculators so you would look for the "^" button and type the following

2^3.58<enter>

If you have a "merely" scientific calculator you will be looking for a key that looks like "x to the yth power" (I can't do it without LaTeX.) I'll call this key <x^y>. You would type in:

2 <x^y> 3.85 , then the equal or enter key.

You should get 2^3.85 = 14.42

-Dan